A difficulty in breast imaging, breast surgery and treatment planning is the fact that the shape of the breast changes significantly with the positioning of the patient, e.g., prone position during acquisition of an MRI image and supine position during surgery or radiotherapy and upright position during optical surface imaging. Alignment of the different views of the breast can be employed to solve this issue in surgical planning and guidance or radiotherapy planning.
To align the different views, standard image based registration is usually not possible since in the standard clinical workflow supine (or even upright) volumetric images are not acquired. Acquisition of these additional images would add a significant complication (time, cost, and inconvenience for the patient) to the workflow and is unlikely to become common practice.
Prone-to-supine breast image registration by inclusion of a biomechanical model, as described in Eiben, B., Han, L., Hipwell, J., Mertzanidou, T., Kabus, S., Buelow, T., Lorenz, C., Newstead, G., Abe, H., Keshtgar, M., Ourselin, S., Hawkes, D.: Biomechanically guided prone-to-supine image registration of breast MRI using an estimated reference state. In: Biomedical Imaging (ISBI), 2013 IEEE 10th International Symposium on. pp. 214-217 (2013), has been found to be promising and successful in many cases. However, between the upright simulation and the optically scanned breast surface (also in upright position) a sufficiently good alignment is not guaranteed. This is to some extent due to the MRI scanning and patient support equipment. Even breasts of carefully positioned patients can show severe skin surface indentations (e.g., due to the MRI coils) especially in the medial region around the sternum.
US 2014/0044333 A1 discloses a system and method for providing registration between breast shapes before and during surgery. A registration framework is presented that registers volumetric breast images captured before surgery with intraoperative surface images. The method comprises the steps of: identifying an air/tissue boundary from a volumetric image created at a first time; processing the volumetric image with an image filter to emphasize the air/tissue boundary; and registering a surface optically scanned image with the filtered volumetric image, where the surface optically scanned image is created at a second time.